Manufacture of folding-cot hardware

ABSTRACT

A METHOD OF FORMING HINGE-PART BLANKS FOR BOTH THE L-SHAPED AND T-SHAPED TWO-PART LEG HINGES USED IN FOLDING COT MANUFACTURE BY STAMPING SAME FROM A METAL STRIP ACCORDING TO A BLANK LAYOUT PROVIDING FOR THE PRODUCTION OF BOTH BLANK SHAPES FROM SAID METAL STRIP WITH MINIMAL SCRAP.

Feb 23, 1971 H. KRAMER 3,564,687

MANUFACTURE OF FOLDING-COT HARDWARE Filed April 29, 1969 2 Sheets-Sheet 1 INVENTOR jvYM/V/V IPA/75,?

, Feb. 23, 1971 H. KRAMER MANUFACTURE OF FOLDING-COT HARDWARE Sheets-Sheet 2 Filed April 29, 1969 I N VENTOR United States Patent Office 3,564,687 Patented Feb. 23, 1971 3,564,687 MANUFACTURE OF FOLDING-COT HARDWARE Hyman Kramer, 2764 E. 16th St., Brooklyn, N.Y. 11235 Filed Apr. 29, 1969, Ser. No. 820,138 Int. Cl. B23 13/00, 17/00 US. Cl. 29150 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to improvements in the manufacture of folding-cot hardware, and more particularly in the manufacture of the leg hinges employed in army cots and like folding structures.

As is well known, the legs of a standard army cot are connected to the side rails thereof by sheet-metal hinges, of which the hinges that connect the pairs of end legs to the ends of the side rails are each made up of two L- shaped parts having rightand left-hand relationship, and the hinges that connect the center legs to said side rails and also provide a hinge connection between the half-length sections of each side rail are similarly each made up of two hinge parts but said parts are T-shaped rather than L-shaped. Thus, each army cot requires a total of six leg hinges, each comprised of two parts, or a total of twelve hinge parts in all, of which eight parts are L-shaped and four are T-shaped.

It becomes readily apparent from the foregoing that the cost of fabrication of the hinge parts in the number and of the different configurations required in the relatively simple structures such as army cots (themselves a low-cost item) of necessity represents a substantial fraction of the manufacturing cost thereof, and it follows that any method of hinge fabrication which simplifies and/or reduces the cost of producing the numerous hinge parts required per cot would be desirable and highly advantageous to the particular industry.

With the above in mind, a general object of the present invention is the provision of a simplified and econmical method of fabricating the leg hinges used in army cot and like structures.

A more particular object of the invention is the provision of a hinge-part fabrication method enabling multiple hinge-part blanks of the proper size and configuration necessary to the formation of the leg hinges used in army cot manufacture and which may bear right and lefthand relationship, to be blanked out from strip stock speedily and with a minimum of scrap or waste.

Yet another Object of the invention is the provision of a hinge-part blanking-out method by which plural hingepart blanks, certain of which bear rightand left-hand relationship and at least one of which has different configuration than the others, may be progressively stamped from a length of strip stock moving through a blankingout press with each working stroke of the die thereof and in such a manner that said plural hinge part blanks may be produced with a minimum of scrap.

The above and other objects of the invention will appear from the following detailed description of the herein proposed method of leg-hinge fabrication, taken with the accompanying drawings in part illustrative of same, wherein:

FIG. 1 is a fragmentary perspective view of a so-ealled army cot which generally depicts the nature and relationship of the leg hinges employed therein, to the fabrication of the blanks for forming same the present invention is directed;

FIGS. 2, 3 and 4 are broken-away side, end and top views of one of the end leg-to-side rail hinge connections characterizing the cot shown in FIG. 1;

FIG. 5 is a perspective view showing one, i.e. the righthand, of the hinge parts employed in the leg-to-side rail hinge connection shown in FIGS. 2-4 inclusive;

FIGS. 6 and 7 are broken-away front elevation and top views, respectively, showing one center leg-to-side rail hinge connection, as seen from the relatively outer and top sides thereof;

FIG. 8 is a perspective View of one of the T-shaped hinge parts making up a center-leg hinge connection as shown in FIGS. 6 and 7;

FIG. 9 is a fragmentary view of a length of strip stock illustrating both a preferred hinge-part blank layout and the manner of progressively blanking out a plurality of hinge-part blanks of different relationship and configuration therefrom with minimal scrap, in accordance with the invention; and

FIG. 10 is a view similar to FIG. 9 but illustrating a different layout of the hinge-part blanks than that shown in FIG. 9.

Referring to the drawings in detail, a typical folding army cot shown to be set up for use in FIG. 1 comprises longitudinal side rails 10, 12 (each made of two halflength sections) bridged by a sheet 14 of flexible material such as canvas or the like which extends transversely therebetween and provides the body-rest portion of the cot; opposite pairs of end legs 16, 18 (of which only one end pair is shown) which are pivotally connected to one another intermediate their ends by a pivot pin or bolt 20 and which are also hingedly connected at their upper ends to corresponding ends of said rails 10, 12 by generally L-shaped sheet metal hinges designated H and H there being corresponding hinges connecting the upper ends of the opposite leg pair (for reference herein designated H and H to the ends of side rails 10, 12 opposite those shown, all of which hinges are of two-part construction whose parts bear rightand left-hand relationship; and a pair of center legs 26, 28 which are pivotally connected to one another intermediate their ends by a double-ended hinge assembly generally designated 30, and are hingedly connected at their upper ends to the adjacent ends of the sections of their associated side rails by T-shaped sheet metal hinges herein referred to as H H (of which only one hinge H is illustrated), also of two-part construction and whose parts have opposed identical, rather than rightand lefthand, relationship.

When set up for use, the side rails 10, 12 of a cot of the type illustrated are usually maintained spread apart by spreader members 24 detachably coupled to the ends thereof, one of which is shown in broken lines in FIG. 1. As the manner in which a so-called army cot employing end and center leg-to-side rail hinge connections as aforesaid folds is well known, no further description thereof is here believed to be necessary.

FIGS. 2-5 inclusive illustrate the detailed construction of the end-leg hinges H H (and also of the opposite end-leg hinges H H from which it will be seen that each said hinge is made up of two separate hinge parts designated h h each of sheet metal and having inverted- L configuration, the horizontal top bar portion of which usually has somewhat shorter length than the vertical bar portion thereof. Preferably, and as best seen in FIG. 5, each of said hinge parts h k is provided along both edges of its vertical bar portion with right-angularly disposed flanges designated f f which extend in the same direction from the bar portion proper and are spaced apart a distance substantially equal to the width dimension of each of the aforesaid end legs 16, 18, whereby said vertical bar portion has shallow channel section, the width of the channel being equal to the width of an end leg whereby a hinge part is adapted to partially enclose an associated end leg when placed thereagainst. Thus, when two hinge parts formed as in FIG. but having rightand left-hand relationship (as determined by the direction of extension of their top bar portions from their vertical bar portions) are assembled to the upper end portion of an end leg 16 or 18 in the relative positions thereof shown in FIGS. 1 and 2 and are thereupon secured to said upper end portion and to one another as by a cross rivet r (FIG. 3), they together provide an upwardly-directed and angled extension of said end leg.

As is also seen in FIGS. 13, the top bar portions of the so-assembled hinge parts I1 11 2 are adapted to receive between them the end portions of a side rail or 12 and also to provide bearing for a pivot pin or bolt 22 extending between said top bar portions and through the interposed side-rail end portions, all as permits collapsing movement of the end legs relative to the side rails which they normally support.

Now referring to FIGS. 6-8 which illustrate in detail one of the center-leg hinges hereinbefore referred to as H H and one of the hinge parts making up same, it will be seen that such again are of two-part sheet metal construction and also that the individual hinge parts have T- rather than L-configuration, as with the prior described end-leg hinges. FIG. 8 shows that the vertical bar portion of each said T-shaped hinge part is also preferably formed with side-edge flanges (designated f f which are spaced apart the width of a center leg, thereby to form a shallowdepth vertical channel for the reception of the upper end of a center leg 26, 28. The views under consideration also show that each of said center-leg hinges H H is made up of a pair of the hinge parts 11 I1 assembled in opposing relationship about and rigidly aflixed to the upper end portion of a center leg 26 as by a cross rivet (or through bolt) r In such position, each center-leg hinge is adapted to accommodate between the oppositely directed, spacedapart top bar portions of the opposed parts making up same the adjacent ends of the two sections of a side rail 10 (or 12), and also to provide mountings for the pivot pins 32, 34 which pivotally connect said side-rail sections to one another and to an associated center leg.

FIGS. 2 and 6 in particular also illustrated that the various hinge parts are preferably provided with reinforcing ribs or embossments e which as shown are L-shaped for L-shaped hinge parts and T-shaped for the T-shaped hinge parts. Said embossments permit the use of substantially thinner-gauge sheet metal in the fabrication of said hinge parts than was previously considered possible. If desired, additional gauge reduction may be safely achieved by subjecting the hinge parts after their fabrication to a hardening treatment.

Corning now to the herein proposed method of fabricating the nuemerous and to some extent differently configured hinge parts required for the aforesaid hinges H H with which the present invention is concerned, reference is had to FIG. 9 which is intended to be illustrative not only of a hinge-blank layout enabling multiple hinge-part blanks, i.e. blanks corresponding to the size and configuration of the required flanged hinge parts but prior to bending of the flanges f f (FIG. 5) and f f (FIG. 8) out of the plane of said hinge parts proper, to be formed from strip-metal stock with a minimum of scrap, but also of the particular multiple hinge-part blanks which are so produced.

A first important step of the herein proposed method is to provide a strip of metal stock S suitable as to its material and its gauge to the fabrication of the required hinge parts therefrom and which further has width exactly equal to the sum of twice the developed width of the vertical bar portion of an L-shaped hinge (H1Hg inclusive), plus 4 the developed width of the vertical bar portion of a T- shaped center-leg hinge (H or H with the term developed width meaning the width of said bar portion proper plus that of its two side-edge flanges which will be ultimately formed thereon but prior to the bending thereof out of the plane of said bar portion proper.

A second important requirement of the herein method is that of providing a progressive sheet-metal blankingout die set up to blank out from said strip S feeding intermittently through same the three partially formed and still connected hinge-part blanks designated B B and B according to the layout thereof illustrated in FIG. 9. Such layout provides that the two blanks designated B and B; which ultimately are to provide both the rightand lefthand hinge parts for an L-shaped hinge (H -H are comprised by strip areas which are disposed symmetrically to the sides of the center line and generally longitudinally along opposite outer-edge zones of the strip S but more particularly are so disposed that their respective sub-area portions which ultimately provide the vertical bar portions of the final hinge parts extend in spaced-apart, parallel relation and with their outer-edge lines (which ultimately define the relatively outer-edge lines of the still flat or unbent flange-forming wings or extensions of said bar portions) coinciding exactly with the side-edge lines of said strip S, all as provides that their relatively inneredge lines will be spaced apart a distance exactly equal to the developed width of the vertical bar portion of the next following center-leg hinge part B to be blanked; and further that their sub-area portions which ultimately com prise the shorter-length horizontal bar portions of said two blanks B,, B are disposed forwardly of said first-mentioned sub-area portions and extend toward but terminate just short of one another.

As to the aforesaid third blank B which ultimately is to provide one of the two hinge parts for a T-shaped centerleg hinge H or H it will be seen that the herein proposed layout provides for the top bar-forming portion thereof being comprised by a crosswise extending subarea of the strip S lying just forwardly of that length portion thereof which provides said horizontal bar portions of the blanks B B and which has strip-length equal to the depth dimension required of the top bar portion of said blank B and by a connected sub-area of said strip which extends centrally and longitudinally forwardly from said crosswise extending sub-area and has length and width corresponding to the length and developed width, respectively, of the vertical bar portion of said blank B FIG. 9 also illustrates that the blank layout of the invention provides that as the blanks B B are formed (to the extent shown in the view), so also is defined at least the vertical bar portion of the next center-leg blank B to be fashioned.

Further in connection with FIG. 9, it is explained that such is also intended to illustrate the strip S after it has progressed through successive preliminary working stations of the aforesaid progressive die, during the course of which such holes p for the passage of rivets, pivot pins or bolts, etc. as are required in the final hinge parts being produced are punched, and the aforementioned strengthening ribs or embossments e are similarly impressed. Preferably also, the short-length cross slots designated .s', which are designed to facilitate ultimate separation and definition of the blanks from the strip, particularly at sharply angled inner corners thereof, are punched in the strip at proper locations at an early die station. Preferably too, the parallel, longitudinally extending, cut lines Z 1 are provided in the strip S as shown prior to the full severance of the blanks 13,, B therefrom, it being understood that such cut lines (if provided) are so positioned as to ultimately define the relatively inner edges of the vertical bar portions of the blanks B B whose outer edges it will be remembered are defined by the side edges of the strip S itself.

The progressive die employed will also be one which will be capable of removing, on a near-final working stroke, the side-edge areas x and y of the strip S represented by light shading, and, on its final working stroke, the similarly shaded area of the strip designated z which up to this stage has connected the aforesaid sub-areas of the strip which ultimately provide the horizontal top-bar portions of the final blanks B and B Preferably, on its final stroke the die will also cut away the small so-called carry webs or strips W1, W2 which up to this stage of operation have joined the partially formed blanks B B with the following crosswise extending sub-area of the strip which is to provide the top-bar portion of the next center-leg hinge blank to be formed.

From the foregoing, it will be seen that the blank layout of the invention makes possible the production of three differently related and/or configured blanks B,, B and B speedily, with the minimum of scrap and with little or no hard labor, and hence at a substantially lesser cost than previously considered possible.

The so-fashioned final blanks B,, B B coming from the progressive die are either collected and stored for later final working and heat treatment (if the latter is considered advisable or necessary) or they are immediately given their final working followed by heat treatment, which working usually includes bending their aforesaid side-wing portions at a right angle to the plane of the bar portions on which they are provided, thereby forming the side-edge flanges f f on the L-shaped blanks B and B and the similar side-edge flanges f f on the T-shaped center-leg blank B To further reduce the cost of the hinge blanks, it is of course possible and within the purview of the invention to fashion said blanks B B B devoid of said side-edge flanges f f f f In the latter case, a narrower and hence less costly strip S can be employed, since said flanges when provided are all formed from width areas of the strip.

The description so far assumes that all four of the endleg hinges H H inclusive are made of L-shaped hinge parts whose horizontal bar portions have the same length, which would be the case for a cot generally as illustrated if its side rails 10, 12 have unequal lengths as accommodates for the longitudinal offsetting of the end leg 18 with respect to the end leg 16 of the pairs thereof, or alternatively if said end legs are formed and pivotally connected by a hinge (such as the center-leg hinge 30) as to swing in the same plane. However, in most armyand related-type cot structures whose end legs are longitudinally offset from one another as in FIG. 1, the horizontal top bars of the two hinges (such as the illustrated one designated H which connect the longitudinally offset end legs 18 of the pairs thereof to their associated side rail are made longer than the corresponding bar portions of the hinges (such as the one designated H which connect the companion end legs 16 to their associated side rail (12 for example) by an amount substantially equal to the aforesaid end-leg offsetting, as permits the use of side rails 10, 12 of equal length.

When such added length is to be given to the horizontal bar portions of the hinge parts for the two L-shaped hinges typified by the hinge H as aforesaid, it is not feasible to use therefor the blank layout shown in FIG. 9, although it is emphasized that such layout is still valid for the fabrication of the blanks for the end-long hinges which connect the two opposite end legs (corresponding to the end leg 16, FIG. 1) to their side rail, and for the fabrication of the blanks for the center-leg hinges H H as well. Instead, for the production of the blanks for the hinges requiring the longer horizontal bar portions as aforesaid, a blank layout according to FIG. 10 is suggested. Such assumes the use of the same width and make-up, i.e. gauge, etc., of strip stock S as used in the FIG. 9 layout, but the progressive die employed is necessarily different, being instead one which is capable of stamping out on each two successive working strokes thereof the two L-shaped blanks designated LB and LB turned and arranged as shown. More particularly, the vertical bar-forming portions of said blanks (including their flange-forming extensions or wings f f are comprised by adjoining sub-areas of the strip- S which extend transversely across its central portion and the horizontal bar-forming portions of said blanks are comprised by strip sub-areas which extend along opposite side-edge portions of the strip and alternately from the opposite ends of said first-mentioned sub-areas. Such a blank layout also results in a minimum of scrap, which latter is indicated by the shaded areas associated with the two forwardmost blanks LB and LB From FIG. 10 it will also be seen that it is contemplated herein that in passing through successive preliminary working stations of the progressive die employed, the strip S will be punched to provide in said sub-areas thereof all such holes p as are required in the final hinge parts being fashioned and will similarly have the strengthening ribs or embossments e impressed in said sub-areas as required. Thus, when the blanks LB and LE come from the die, they are complete except for the final operations of bending the flange-forming wings provided on the blanks (if such are provided) and heat-treating the final hinge parts fashioned from said blanks.

While the method of the invention so far described is specific to the fabrication of hinge-part blanks of generally planar type, as adapts them to the sections of cot legs and/or cot side-rails of square or rectangular section, it is to be understood that the herein method is also applicable to the fabrication of the blanks for the leg hinges of folding cots whose legs in particular have circular section. For such latter applications, the vertical bar portions of blanks will be shaped in a final operation to conform to the surface curvature of said tubular legs, rather than to channel section as shown in FIG. 5 and 8, for example.

As the above-described method of and layout for hingepart blank fabrication is susceptible to variations as would suggest themselves to persons having ordinary skill in the field of sheetmetal hinge manufacture, it is intended that the herein description and accompanying drawings are to be taken as illustrative and not as limiting.

I claim: 1. The method of fabricating the blanks for the twopart sheet metal hinges of the type employed in folding cots and like structures from a metal strip with minimal scrap, which blanks have configuration providing same with substantially right-angularly disposed bar portions, which comprises the steps of:

providing an elongate strip of suitable sheet metal having predetermined width which is substantially equal to the sum of certain critical dimensions of the bar portions of two said blanks to be fabricated;

blanking-out from an end-length portion of said strip as the latter is advanced in the direction of its length at least two said blanks according to a layout thereof on said strip providing that corresponding bar portions of said two blanks are comprised by spacedapart sub-areas of the strip which extend longitudinally along opposite side-edge portions thereof and which are defined along corresponding relatively outer side edges thereof by the longitudinal side edges of said strip, and further providing that the right-an-gularly related bar portions of said two blanks are comprised by crosswise-disposed sub-areas of said strip which extend in opposite directions from said first-named sub-areas; and

repeating said blanking-out operation on successive end-length portions of said strip as the latter is advanced in the direction of its length.

2. The method of fabricating the blanks for the twopart sheet metal hinge of the type employed in folding cots and like structures from a metal strip with minimal scrap, which hinges are characterized in that certain thereof are each made of two L-shaped sheet metal parts and others are each made of two T-shaped metal parts as results in all said parts having generally right-angularly dis posed first and second bar portions, which includes the steps of:

providing an elongate strip of sheet metal having predetermined width which is equal to the sum of the Width dimensions of corresponding first bar portions of a plurality of hinge-part blanks to be fabricated at any one time; and blanking-out from a relatively short-length portion of said strip said plurality of blanks according to a layout thereon providing that said first bar portions of said plurality of blanks are comprised by sub-areas of the strip disposed immediately adjacent one another and which extend in the direction of the length of said strip and which together occupy substantially the full width of said strip, and further providing that the second bar portions of said plurality of blanks comprise transversely extending sub-areas of the strip lying just forwardly and rearwardly of the aforesaid longitudinally extending sub-areas thereof. 3. The method according to claim 2, wherein all said first bar portions have side-edge flanges thereon, and wherein the width of the metal strip is such as to provide the aforesaid sub-areas thereof which comprise said first 25 bar portions with width sufiicient for the formation of said side-edge flanges thereof.

4. The method according to claim 2, wherein said balnks to be fabricated comprise two blanks having L- shape and one having T-shape, and wherein said layout provides that the two blanks having L-shape are comprised by two outer-edge, laterally spaced and longitudinally extending sub-areas of said strip and transversely extending and connecting sub-areas thereof which lie immediately forward of said spaced-apart sub-areas, and that said one blank of T-shape comprises a transversely disposed sub-area of the strip lying immediately forwardly of said outer-edge and connected sub-areas thereof and a forwardly-centrally disposed sub-area extending longitudinally from said last-named transversely disposed subarea and which has width equal to the spacing between said outer-edge sub-areas.

References Cited UNITED STATES PATENTS 876,195 1/1908 Kittleson 29415X 2,135,723 11/1938 McCallum 29-11 2,327,669 '8/ 1943 Richard 29-15OX THOMAS H. EAGER, Primary Examiner US. Cl. X.R. 29-11, 415 

